Omega-3 vetzuren tegen onvruchtbaarheid man*
Uit een studie, weliswaar met muizen blijkt dat het omega-3 vetzuur
docosahexaeenzuur (DHA) wel eens de oplossing kan zijn bij
vruchtbaarheidsproblemen bij mannen. Het lichaam kan zelf in beperkte mate DHA maken uit
alfalinoleenzuur. Deze studie zou wel eens het antwoord kunnen zijn op eerdere studies die vaststelden dat bij weinig en slecht sperma ook lage bloedwaarden DHA werden vastgesteld. Bij de muizen in de studie ontbrak een gen om DHA aan te maken en daardoor waren deze muizen zo goed als onvruchtbaar. Door aan hun voeding DHA (0,2 gewichtsprocenten van de voeding) toe te voegen bleken al de muizen weer normaal vruchtbaar te zijn.
New research: omega-3s may treat male infertility
More than two million married couples in the U.S. are unable to conceive a child and, according to the National Institutes of Health, male infertility is the cause about 40% of the time. Now a University of Illinois (UI) study recently published in the Journal of Lipid Research offers hope that omega-3 fatty acids can help many infertile men become fathers one
day.
UI scientists came up with this discovery while investigating docosahexaenoic acid (DHA), an omega-3 the body can make from alpha-linolenic acids found in vegetable oils, including soybean and canola oils. DHA is already known to be important for the development of the body's nervous system. But it turns out DHA also may correct two major causes of male infertility -- low sperm counts and abnormally shaped
sperm.
"In our experiment, we used 'knockout' mice that lacked the gene responsible for an enzyme important in making DHA. In the absence of DHA, male mice are basically infertile, producing few if any misshaped sperm that can't get where they need to go," Manabu Nakamura, a UI associate professor of food science and human nutrition, explained in a press statement.
When the research team analyzed the amount, shape, and motility of the animals' sperm, the mice lacking DHA simply were not able to reproduce. In fact, in the DHA-deficient mice, sperm counts were not only extremely low but the sperm the animals produced were abnormally shaped. Instead of being elongated and able to move quickly, their sperm were round and sluggish.
However, when DHA was introduced into the animals' diet, a dramatic change took place. The previously infertile mice soon had completely normal sperm and their fertility was totally restored. Bottom line: DHA restored all observed impairment in male reproduction.
"It was very striking. When we fed the mice DHA, all these abnormalities were prevented," Nakamura said.
While the new research involves animals and not people, it is the first to show a direct link between DHA and male fertility levels. And this association could offer an explanation for previous studies that found male fertility patients with low sperm counts and slow moving sperm tend to have low levels of
DHA.
Abstract
Docosahexaenoic acid supplementation fully restores fertility and spermatogenesis in male delta-6 desaturase-null mice.
Roqueta-Rivera M, Stroud CK, Haschek WM, Akare SJ, Segre M, Brush RS, Agbaga MP, Anderson RE, Hess RA, Nakamura MT.
Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Delta-6 desaturase-null mice ((-/-)) are unable to synthesize highly unsaturated fatty acids (HUFAs): arachidonic acid (AA), docosahexaenoic acid (DHA), and n6-docosapentaenoic acid (DPAn6). The (-/-) males exhibit infertility and arrest of spermatogenesis at late spermiogenesis. To determine which HUFA is essential for spermiogenesis, a diet supplemented with either 0.2% (w/w) AA or DHA was fed to wild-type ((+/+)) and (-/-) males at weaning until 16 weeks of age (n = 3-5). A breeding success rate of DHA-supplemented (-/-) was comparable to (+/+). DHA-fed (-/-) showed normal sperm counts and spermiogenesis. Dietary AA was less effective in restoring fertility, sperm count, and spermiogenesis than DHA. Testis fatty acid analysis showed restored DHA in DHA-fed (-/-), but DPAn6 remained depleted. In AA-fed (-/-), AA was restored at the (+/+) level, and 22:4n6, an AA elongated product, accumulated in testis. Cholesta-3,5-diene was present in testis of (+/+) and DHA-fed (-/-), whereas it diminished in (-/-) and AA-fed (-/-), suggesting impaired sterol metabolism in these groups. Expression of spermiogenesis marker genes was largely normal in all groups. In conclusion, DHA was capable of restoring all observed impairment in male reproduction, whereas 22:4n6 formed from dietary AA may act as an inferior substitute for DHA.
PMID: 19690334 [PubMed - indexed for MEDLINE] (Juli 2010)
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